It is known in the art to prepare azo compounds from a tertiary amine.
U.S. Pat. No. 3,783,148 (Fuchs, Jan. 1, 1974) relates to the preparation of symmetrical azo compounds by the following reaction: ##STR4## In the above reaction R.sub.1 is alkyl of from 1 to about 6 carbon atoms, optionally substituted with an alkoxy group of 1 to about 4 carbon atoms; R.sub.2 is cycloalkyl of from 3 to 6 carbon atoms or alkyl of from 1 to 6 carbon atoms; R.sub.3 is a radical selected from the group consisting of --CN, --COOR, and --COOM, where R is an alkyl radical of from 1 to 6 carbon atoms, and M is sodium or potassium; with the proviso that R.sub.1 and R.sub.2 together contain a total of at least 4 carbon atoms, and with the further proviso that R.sub.1 and R.sub.2 can be taken together and are alkylene of from 3 to 11 carbon atoms. The coupling reaction occurs in the presence of at least 95 percent by volume of a C.sub.1 -C.sub.2 alcohol.
U.S. Pat. No. 4,028,345 (Moore, Jr., June 7, 1977) relates to an improved process for the preparation of aliphatic azo compounds. ##STR5## wherein R.sub.1 and R.sub.2 are selected from the group consisting of aliphatic hydrocarbon radicals of 1 to 8 carbons, optionally substituted with a carboxyl group, a hydroxyl group or an alkoxy group represented by --OR wherein R is an acrylic aliphatic hydrocarbon radical of 1 to 4 carbon atoms; x is the valence of the M ion and a surface active compound selected from the group consisting of an anionic, cationic, nonionic, amphoteric and mixed surface active agents or surfactants. More specifically, this reference relates to a process for the preparation of aliphatic azodinitrile compounds by reacting an aqueous hypochlorite solution with an aminonitrile in the presence of a surface active agent.
The above aminonitriles utilized for the preparation of the azo compounds are prepared in a pressure vessel by reacting a ketone with ammonia gas. The vessel is cooled in a dry ice acetone bath. Hydrogen cyanide is then introduced in portions in an amount equivalent to that of the ketone. The reaction vessel is warmed to room temperature and pressurized to 50 psig with ammonia, heated to 40.degree. C. and 50 psig for 8 hours and cooled to yield an aminonitrile according to the equation below: ##STR6## The above references teach the preparation of symmetrical and non-symmetrical azo compounds. In both references, fairly pure aminonitrile is utilized as a starting material for reaction with the metal hypochlorite ##STR7## In the past it was thought that an excess of ammonia was to be avoided in the preparation of the aminonitrile since it might interfere with the coupling reaction: ##STR8## Additionally, water was to be avoided as a solvent in the preparation of the aminonitrile since the water might promote undesirable reverse reactions: ##STR9##
Within the present invention the aminonitrile is formed utilizing a solvent; however, the aminonitrile is not recovered.